libsmb2 through 6.2 contains an integer underflow vulnerability in decodeacl that allows malicious SMB servers to trigger heap out-of-bounds reads via crafted security descriptors. Attackers controlling a server or intercepting unsigned sessions can send an AclSize below 8 in a QUERYINFO reply, bypassing ACE bounds checks and crashing the client.

libsmb2 through 6.2 contains a heap out-of-bounds read vulnerability in smb2decodefilefsvolumeinfo and smb2decodefilefsattributeinfo that allows malicious SMB servers to read past reply buffers. Attackers controlling a server or intercepting unsigned sessions can send crafted QUERYINFO replies with missing or oversized name lengths to crash the client.

libsmb2 6.2+ is vulnerable to Buffer Overflow. When processing SMB2 chained PDUs (NextCommand), libsmb2 repeatedly calls smb2addiovector() to append to a fixed-size iovec array without checking the upper bound of v->niov (SMB2MAXVECTORS=256). An attacker can craft responses with many chained PDUs to overflow v->niov and perform heap out-of-bounds writes, causing memory corruption, crashes, and potentially arbitrary code execution. The SMB2OPLOCKBREAK path bypasses message ID validation.